A now-classic 2011 interview with former Secretary of Defense Donald Rumsfeld features Louis C.K. repeatedly asking the ex-Congressman and former Nixon staffer whether he is a "flesh-eating lizard from outer space" who "eats Mexican babies." But as Errol Morris shows in his new documentary, The Unknown Known, Rumsfeld is not an otherworldly villain with a forked tongue, but a boring idiot in a shiny suit who presided over some of the most catastrophic and shameful policies in U.S. history.

Morris, who won an Oscar in 2004 for his study of Vietnam-era Defense Secretary Robert McNamara, The Fog of War, has Rumsfeld read from his vast trove of internal memos ("Snowflakes") penned throughout his career in government to paint a portrait of a patriotic pedant. Rumsfeld agonizes over the exact definition of the word "insurgency," but from his insistence that Saddam Hussein had helped plan 9/11 to his refusal to acknowledge that the torture techniques he approved led to severe abuses of power, it's clear that Rumsfeld's etymological inquires are utterly bogus. For anyone alive since 2001, Morris's brilliant film provokes teeth-grinding, shoe-tossing rage.

"We want our evil served up to us in a certain way," Morris recently told me over a small mountain of empty coffee cups in a hotel lobby. "We want to be shown the cloven hoof. But in a story like this, the cloven hoof, the sign of the beast, does not pop out. What pops out is unpleasant, pathetic, ordinary human stuff. Mediocrity. Self-satisfaction. Vanity. A clueless belief in your own bullshit."

What happened with Bill Maher? I thought his objections to the film were contradictory. He essentially said you picked on the wrong guy, but you were also too easy on him. Were you surprised by his reaction to your movie?

I would characterize it slightly differently. It was certainly surreal. All of the sudden, I'm seemingly confronted by a vociferous Rumsfeld supporter—how smart he is, how articulate he is. I remember bits and snatches of it. Like sepia-toned combat footage in a movie.

Are you surprised that people would think you were too easy on him? I thought you let Rumsfeld hang himself in the movie with his own words.

I'm not surprised by anything. Bill Maher seemed—and you may have a better answer to it than I do. You start off in a chess game: white makes a move, black makes a move, white makes another move, black makes another movie and you get locked into a certain kind of battle. If he wants to say how smart Rumsfeld is, fine. If he wants to tell me how profound Rumsfeld's comment is that "time will tell" whether invading Iraq was a mistake—'cause guess what? I don't find it terribly profound.

Time will tell?! Again, on the level of Chinese fortune cookie philosophy. He presided over truly disastrous policies. But if we wait long enough, even the Mongol invasions are going to look humane.

How much of that myth do you think he truly believes in? And how much of that is a constructed persona that he uses as political cudgel?

That is the central mystery of the movie. A friend of mine, Ron Rosenbaum, is just publishing a new edition of a book he wrote 20 years ago Explaining Hitler. It's a meta history of Hitler's evil, talking to various historians and philosophers who've written about Hitler. And one section appeared in The New Yorker and it was an argument between two very famous British historians Alan Bullock and Hugh Trevor-Roper. Trevor-Roper was later disgraced for the authentication of the Hitler diaries.

Their argument was: was Hitler, say, an aluminum siding salesman who was selling a product to the German people but had no great belief in that product himself? He saw it as a tool to an end he was trying to achieve. Versus a different interpretation, where Hitler is The True Nazi and The True Believer—the person essentially who believes in his own bullshit. Now, it can be both. I don't think it has to be A or B. But it's worth really thinking about and writing about. There's a slippery slope where you do start to believe in your own bullshit.

We've already hit the Godwin's Law of the interview, Hitler's come up when talking about Rumsfeld. You've interviewed serial killers, and "bad people." Where does Rumsfeld rank on this scale?

You can remove the quote-unquote from the bad people.

Ha, OK. You've said before that while there is such a thing as objective truth, everyone practices self-delusion. A frequent theme in your films is self-delusion. So where does Rumsfeld rank on the self-delusion scale? Do you view him as someone who truly is that historically devastating as a Hitler? Or is he no worse than someone in Vernon, Florida?

Well, you're factoring so many things into that question. Rumsfeld has immense power. He controlled the most powerful military apparatus in history. That has to be taken into account. He also was in possession of these working principles which were really, really, when you look at them, nefarious. I don't know how else to describe them. Nefarious seems too kind.

I'll give you an example. Working principles like, "absence of evidence is not the evidence of absence." He wrote this in one of these snowflakes that he sent to the President. I think he sent a version of this twice in the early years of the Bush administration. I see the Airedale president reading this material, and how is it intended? It was intended with respect to WMD in Iraq. If you can't find WMD in Iraq that doesn't mean it isn't there. As my son would often say: it's not lost I just don't know where it is.

And where did that expression come from? I trace it back to its origins. It came from the British astronomer, president of the Royal Society, Master of Trinity College, Martin Rees, O.M. He wrote about it with respect to SETI, with respect to the possibility of intelligent life somewhere else in the universe. So the universe, correct me if I'm wrong, is taken to be a pretty big place. Bigger than say, New Jersey.

Bigger than Iraq.

Bigger than Iraq. So you're rooting around in the universe, you can't find signals from intelligent life, but, you know, maybe you didn't look in the right place in the right way. So Rees and Carl Sagan popularize it and it's picked up by the Anti-Ballistic Missile Commission. Now it's taken on a new context, a new meaning. In the extreme form, the example I give in my New York Times essay, someone says there's an elephant in the room. You open the door, you look around for the elephant, you look in the closets, pull out all the drawers in the bureaus, you bend down and peek under the bed. No elephant. Absence of evidence? No, I don't think so. Evidence that there is no elephant in the room? Looked in the drawers, bent down, peered under the bed, etcetera etcetera. No elephant.

An expression that seems to have meaning in one context has a radically different meaning in a different context. And taken to some absurd conclusion you can use that principle, the absence of evidence isn't an evidence of absence, to justify anything. If you were to be kind, it's a form of anti-reason, anti-empirical, anti-science.

When Rumsfeld's writing these memos—

But the question is does he even know what he's doing?

Yes.

You're asking me? No, I don't think so. I think he's glib, I think he's facile, I think he's empty, I think in heart he's a salesman and not a thinker, I think he's an extremely dangerous nincompoop.

Two weeks after 9/11, Rumsfeld and Bush are in the Oval Office. Bush says we need a "creative" plan to invade Iraq, and by the way, I heard about your son who is struggling with drug addiction, and I'm here for you. Rumsfeld breaks down and cries. He sobs on Bush's shoulder. It's this really charged moment. That seems to paint a more nuanced portrait than this cold nincompoop you just described. Did you ask Rumsfeld about that incident? Was any topic off-limits?

By the way, I would not say the two are incompatible. One of the things that makes it hard to write about Rumsfeld is, here's a guy who bent over backwards to cooperate with me. More so than Robert McNamara. Unendingly charming, cooperative, supplied the snowflakes, read the snowflakes on camera, and yet in the end, I'm left with this terrible, terrible unease.

Because he was essentially selling you aluminum siding for 34 hours? He was the salesman for 34 hours straight and didn't crack an inch?

Well, he cracked unendingly. I mean, there's cracked and cracked. What would you imagine cracking to be?

There's a point where he says that the torture techniques that he authorized at Guantanamo did not "migrate" over to Abu Ghraib and cites a report. You read him a line from that very report that states that the techniques did migrate from Guantanamo to Abu Ghraib. Clearly this is a contradiction. All Rumsfeld does is agree with what you read. I guess for me a crack would be, "We were wrong," or "I was wrong about X". Not even an apology, just an acknowledgement of wrongdoing, of a mistake. Even a mistake that he had misremembered the memo!

He was never going to do that. That's part of the story.

Never going to apologize or never going to admit that he was wrong?

He was never going to do either of those things. He might in the abstract say that we're fallible and we can make mistakes, although the doesn't really go there either. But no, he's not gonna admit to wrongdoing. The closest he comes in Abu Ghraib is simply saying it was on his watch and he would resign. Basically you can see all these moves ratchet into place where he's telling you, "I was not directly responsible for any of this stuff. These things didn't migrate from Guantanamo."

By the way, I made a movie about Abu Ghraib, Standard Operating Procedure. People somehow don't quite see this clearly. When Sabrina Harman, Lynndie England, and Megan Ambuhl, walked in to Abu Ghraib on the hard site, day one—this was their first day—they have their digital cameras. Principally, Sabrina Harman takes pictures. To me, they're the strongest pictures of them all, not the most infamous pictures but the strongest, and she takes pictures of people standing for hours at a time, nudity, holding, stress positions, tra-lalalalala.

Basically a laundry list of stuff Rumsfeld just read in the Haynes memo. How did that stuff get there? By the waving of a magic wand? Those grunts who were court marshaled and imprisoned for all of this stuff, they created excesses of it later, but in essence, it was there on day one when they walked into the prison.

Did Rumsfeld see Standard Operating Procedure? Or did he tell you he saw it?

Of course not. I mean, I don't know for sure but he's not the kind of guy who is intellectually engaged on that level. If I were Donald Rumsfeld and I was coming to interview me would I watch it? Yes, I would watch it. Did he? I doubt it. Did he watch The Fog of War? I doubt it.

You get this great clip of him in the early '90s where he's talking with a group of other former defense secretaries and he says, "The credit [for winning the Cold War] belongs to people who are carped at." Do you feel that because so many people have criticized him and the Bush administration, he feels that criticism vindicates him?

I would put it even more specifically. Do you feel that he is speaking about himself?

Yes.

I would respectfully submit that in every portion of the film he is speaking about himself. It's kind of amazing, and I couldn't include it in this movie, to hear what McNamara has to say at that same session. There he is, sitting at the table next to Rumsfeld. McNamara's saying, he's visited Soviet dignitaries when was president of the World Bank, and they had to step over bums lying on heating grates in Washington. McNamara says something to the effect that with such enormous income inequality and poverty, there will never be the solutions to the biggest problems of the world.

And Rummy is saying the brass ring on the merry-go-round goes to those people like himself who stood fast against Soviet aggression, made our country strong and who ultimately brought down the Soviet Union as a result.

I make these movies and they give me this overwhelming feeling of despair. With Rumsfeld, and I have a guilty conscience, I don't know how else to describe it, you don't want to spend this much time with someone and then come away just feeling icky poo. Like you've been soiled. He's been gracious, he's been kind, he's been forthcoming after a fashion. I come away kind of appalled.

It's interesting how really smart people can be taken in. Sometimes you just need to survey the responses to this kind of thing. I was reading this morning in the Times the 20 or so responses to the first piece of the essay. And I would say 19 out of 20 hate Rumsfeld so much that can't contain themselves. They just want to have at it. Others feel that it is worth examining rather than just simply condemning. Or if you prefer, examining and then condemning. I think there's a lot to examine in what went on in that administration. The failure of the news media ultimately to confront what was going on, Rumsfeld's extraordinary sales job in presenting gobbledygook as rationality, people trying to call him on it but never really being able to call him on it. I'm rather sympathetic with those journalists because it is clear to me that they tried even if they didn't succeed, knowing the difficulty.

How much do you think their hands were tied by the spirit of the times? The nationalistic fervor that basically held the country in this thrall until 2007? That asking probing questions was unpatriotic.

Wrong time, wrong place. It's all puzzling. Puzzling because we know that these people will never really be held accountable for what they've done. Never. And we're reminded of that fact. We were reminded of that fact yesterday, when Rumsfeld started comparing Obama invidiously to a monkey. These ideas that you were expressing had a really deep and nefarious consequences, and I don't even think he knows that. I think he was trying to spin a world more to his liking either by gerrymandering dictionary definitions and vocabulary, denial, misdirection, but almost as a man out of control. I don't see him as the puppeteer. I see him as the some crazy neo-Shakespearean figure lost in his own bullshit, his own vanity, and his own greed for power.

Often in Shakespeare the characters know they're bad; Iago knows he's up to no damned good; Lady Macbeth knows that she might not be the nicest person on the planet; Richard III has moments of insight. These people are really clueless. Rumsfeld is right—they're not Shakespearean in that sense—they're aggressive, they're calculating, they're conniving, but he's lost in a Looney Tunes world of his own devising. I would submit that it's Mr. Rumsfeld that's gone down the wrong rabbit hole, not I.

With your film's release, do you foresee Rumsfeld popping up again and trying to inject himself in the national conversation?

What do you think?

Probably.

Inevitably.

Well, Cheney has sort of settled down. Though that may be his health.

Cheney and Rummy are different critters. Radically different critters. Remember, Cheney was never the front man. Yes, he was chief of staff for Ford, Vice President for George W. Bush, but Rummy is a performer. He really is, make no mistake. It was shocking the first day I interviewed him. McNamara wasn't even gonna be interviewed yet—maybe I'll do it, maybe I won't, maybe I'll stay for ten minutes, maybe I won't, maybe I'll stay for another ten minutes, maybe I won't, maybe I'll stay for an hour, maybe I won't, maybe I'll stay for two hours, maybe I won't, maybe I'll come back tomorrow maybe I won't. McNamara doesn't make small talk with anybody. He just does it. Rumsfeld comes into the studio and he's talking to the gaffers and the grips and the makeup people. He's a politician. He came out of politics.

Didn't Cheney as well?

Cheney did not come out of politics. Cheney came out of a number of failures: thrown out of Yale and University of Wyoming and the University of Wisconsin and then he became a bureaucrat. He applied for various jobs in Washington. He was rejected by Donald Rumsfeld the first time around, reapplied, was accepted, and then became Donald Rumsfeld's mini-me for many jobs in the Nixon White House and the Ford White House until he essentially became chief of staff when Donald Rumsfeld became Secretary of Defense.

I sometimes think that Rumsfeld was Nixon's mini-me. That Nixon saw someone as treacherous, as ruthless, and as ambitious as himself and just felt the need to stand up and applaud.

When he started working for Ford, Rumsfeld talks about a giant safe in his office that he inherited from the Nixon administration that he couldn't open. Did you ever figure out what was in that safe?

Nothing.

Is it safe to say that's a metaphor for Rumsfeld? That everyone is wondering what's in Rumsfeld's safe and there's nothing in Rumsfeld's safe?

Yes, I think it is. It is a metaphor that runs through it. That fear of nothing, the need to do everything according to some set of bureaucratic rules and guidelines. I just wanted [the safe] out of my office, he says. One reviewer, a guy from the Daily Telegraph said to me, "Do you think the movie is too subtle for people?" My answer is, yes. I do worry about that. But it's not just simply political commentary, it is art. It's all there: the metaphors, the sea of words, the descent into what I would call madness, the idea that you can hold reality at some remove if you create enough paper swirling around you, that you can create almost a bubble universe.

There's a danger, of course, when you start explaining your own metaphors that you sound like an asshole, but I'll take that risk. And his own absolute, unwavering conviction in his own rectitude. The smile, the rictus. I like myself. I am a good guy. I won. It's a horror movie. We want our evil served up to us in a certain way, we really do. We want to be shown the cloven hoof. We want to see the empty cuff. You wanna ask the question: what's in the cuff? What's in there? And I'm so lightly evasive [Morris lets his fist peek out of his sleeve] Now, out pops the sign of the beast. That's the hope. But in a story like this, the cloven hoof, the sign of the beast, does not pop out. What pops out is unpleasant, pathetic, ordinary human stuff. Mediocrity. Self-satisfaction. Vanity. A clueless belief in your own bullshit.

This line of Rumsfeld's, that Pearl Harbor was a failure of the imagination. Now I really like that one. So let me see if I can think about this carefully: If Pearl Harbor was a failure of the imagination, then perhaps Pearl Harbor could have been prevented if we had just a little bit more imagination. Maybe, say, the imagination to imagine Pearl Harbor before Pearl Harbor, or imagine 9/11 before 9/11.

So the example I give, I call it the Chicken Little Syndrome. So Chicken Little is sitting in the barnyard and an acorn falls on his head and Chicken Little concludes the sky is falling. No lack of imagination there. Chicken Little is on top of it—the sky is falling! Chicken Little gets himself all worked up, starts running around the barnyard, terrorizing all the other barnyard animals, "The sky is falling the sky is falling!" Henny Penny gets bent out of shape, Ducky Lucky, Goosey Loosey, Turkey Lurkey, all agitated, all running around, all upset. After all, the sky is falling. And Foxy Loxy is looking at all of this somewhat entertained and hungry and he uses this as an unparalleled opportunity to eat all of them. Yum. Yum. Yum.

And I say the moral to the story is that if Chicken Little had exercised just a wee little less imagination, she and her barnyard friends might be with us today.